The session cleanup thread won't destroy the session if it is still locked (for any reason, including your own code or 3rd party's code).

Do you have any other frameworks (TMS or CG Dev Tools) in this application?

What's the request which created the session and why there is no other request following it? Under normal circumstances there will be multiple requests when a session start, not a single one, unless it was not handled by a real browser (a bot, search engine or some attack attempt might also cause it)

Many thanks for Your answer.
I have no explicit lock on sessions. The fact is that users are not vary appy to use an application that checks their full activity. I do not kow wat happens about the need to restart the service.
If you have no other suggestion about, please consider this post as closed.
Thank you very much again